Add dollar sign to install command (#52)

* Add dollar sign to install command

* Change syntax highlight for command

Author: lex111

content/docs/en/routing/vue-router.md

@@ -8,8 +8,8 @@ then you'll be happy to learn [the Vue router](https://router.vuejs.org/en/) is
 
 ## Installation
 From a command prompt, run:
-```bash
-npm i vue-router --save
+```shell
+$ npm i vue-router --save
 ```
 
 ## Usage